The drug favipiravir has shown promise as an antiviral therapy in mouse models of Ebola virus infection. Researchers believe it works by inhibiting the RNA-dependent RNA polymerase of Ebola. You would like to test this hypothesis by directly measuring how well favipiravir inhibits this polymerase in vitro. To do so, you measure RNA polymerase activity with the nucleotide substrate present at a concentration equal to twice its KM value. The results of the assay are below:
Favipiravir (μm)
Units of RNA polymerase activity
0
80.4
0.5
72.5
1
65.6
1.5
61.8
2
53.3
5
47.9
10
40.2
25
21.1
50
11.2
100
8.4
Table
1.
What is the IC50 for favipiravir in this polymerase activity assay?
Suppose that the results from a Phase I clinical trial suggest that a circulating concentration of 500 nM favipiravir is the safest dose for human patients. Given this information, which of the following statements is true?
